Temperature responsive variable means for controlling flow in turbomachines



April 18, 1961 B. H. ROWLETT EI'AL 2,980,394

TEMPERATURE RESPONSIVE VARIABLE MEANS FOR CONTROLLING FLOW IN TURBOMACHINES Filed Nov. 23. 1956 2 Sheets-Sheet 1 Fig. 2

ALEXANDER S/L VE'R,

IN V EN TORS.

April 18, 1961 B. H. ROWLETT ETAL 2,980,394

TEMPERATURE RESPONSIVE VARIABLE MEANS FOR CONTROLLING FLOW IN TURBOMACHINES Filed Nov. 23. 1956 2 Sheets-Sheet 2 I 23a I {In 558 H. ROW/.577, ALEXANDER SILVER,

INVENTORS.

United g TEMPERATURE RESPONSIVE VARIABLE MEANS gOR CSONTROLLING FLOW IN TURBOMA- Beb H. Rowlett, Playa Del Rey, and Alexander Silver, Tarzana, Califi, assignors to The Garrett Corporation,

Los Angeles, Calif., a corporation of California Filed Nov. 23, 1956, Ser. No. 623,913

, 4 Claims. (Cl. 253-52) control means to vary the flow to make most eflicient use of the thermal energy contained in the fluid when it is used to operate a turbomachine.

Turbines may be usedto produce power to meet a minimum requirement and are also provided with fixed area inlet nozles. The turbines are designed to produce a desired minimum power output when operated by a compressed fluid having given flow and thermal energy components. When temperature of the fluid increases, such turbines operating theron produce an unwarranted increase in power output relative to the desired minimum.

In some cases the overproduction of power occasioned by an increase in the fluid temperature is wasteful and therefore contributory to ineflicient use of the thermal energy.

Cooling turbines, when operated by means of compressed air bled from aircraft main engines, are subjected to changing temperatures at the inlets thereof, due to varying power output of the aircraft engine during varying flight conditions of the aircraft. In the operation of cooling turbines for conditioning a compartment of the aircraft, it is sometimes desirable to maintain a substantially constant refrigeration output of the cooling turbine. In order to maintain a constant refrigeration output of the cooling turbine when the temperature of compressed air at the inlet thereof varies, the present invention employs a temperature responsive variable area nozzle to control flow through the cooling turbine.

In the operation of cooling turbines, a temperature responsive variable area nozzle may be used to reduce flow through a cooling turbine when temperature of the flow at the inlet thereof is reduced. In this manner a temperature responsive variable area nozzle, in connection with a cooling turbine, conserves pneumatic energy bled from the compressor of an aircraft engine. At the same time it also assists in controlling refrigeration provided by the turbine for use in a compartment of an aircraft.

It is an object fo the present invention, therefore, to provide a temperature responsive variable means for a turbomachine to conserve the thermal energy component of a compressed fluid flowing therethrough, while the turbomachine is producing a constant power or refrigeration output.

Another object of this invention is to provide a temperature responsive variable means which will control fluid flow through a turbornachine in proportion to the thermal energy of the fluid.

Still another object of this invention is to provide a novel combination of a temperature responsive device operably connected with a variable inlet device to control fluid flow through a turbomachine.

res Fatent 11i Further objects and advantages of the invention will appear from the following specification, appended claims and accompanying drawings in which:

. Figure 1 is a sectional view of a temperature responsive variable means, according to the invention, shown applied to a turbomachine;

Fig. 2 is a sectional view taken through line 2-2 of Fig. 1 showing a cross section of one of the temperature responsive elements;

Fig. 3 is an enlarged perspective view of a portion of the variable area nozzle device shown in Fig. 1;

Fig. 4 is a sectional view of a modified form of the temperature responsive variable means a turbomachine;

Fig. 5 is a sectional view taken through line 5-5 of Fig. 4 showing the mounting of one of the temperature responsive elements;

Fig. 6 is a sectional View of another modified form of the temperature responsive variable means shown applied to a turbomachine; and

Fig. 7 is a sectional view taken through line 77 of Fig. 6 showing the linkage used to actuate the variable area nozzle means.

Figs. 1 to 7 illustrate several species of a temperature:

responsive variable means, according to the present invention. As shown in Figs. 1 through 5, the temperature responsive variable means employs a bimetal element located in a turbine inlet plenum and which is used to' actuate a variable area device to control fluid flow through a turbine wheel. As illustrated in Fig. 6, a temperature responsive element disposed to sense temperature at the outlet of a turbine wheel isdesigned to actuate a variable area nozzle to control fluid flow at the inlet of the turbine wheel.

According to the present invention, a specific application of the temperature responsive variable means is an aircraft cabin coolingturbine driven by compressed air bled from the compressor of the aircraft engine. When the aircraft engine is operating at a varying power output, the bleed air flow through the cooling turbine is continually controlled by a temperature responsive variable means. The temperature responsive means willoperate the cooling turbine at the desired refrigeration output while utilizing a minimum amount of compressed air, thus conserving power of the aircraft engine furnishing the compressed air.

Fig. 1 illustrates a conventional cooling turbine comprising a housing 1, in which a wheel 2 mounted on a shaft 3 is rotatably supported by a bearing 4. Located at the periphery of the wheel 2 is an' inlet plenum 5, which directs fluid flow to the wheel 2. A temperature responsive means is mounted within the plenum 5 and includes a variable area nozzle actuated by plurality of bimetal elements 6. Each bimetal element 6 is fabricated from individual sections of two laminated metallic strips 6a and 6b which have different coeflicients of expansion. The strip 6a should have a larger coeflicient of expansion than 6b. Each bimetal element 6 is constructed in a corrugated form from a plurality of individual sections of the two strips (in and 6b with the strip 6a, which has the largest coefiicient of expansion, being placed on the outside of each fold as shown in Fig. 1. The individual sections are jointed together to form a complete element by any desired means such as welding or the like.

The elements 6 each have one end attached to the plenum 5 by a bolt 7a or other suitable fastening means.

ported by a plurality of circumferentially-spaced guide, rods 8 and is provided with axially projecting vane ele- Patented Apr. 18, 1961 shown applied to V 8 when the mov ablei ments '9, 'which' are interleaved or meshed with conformingelern'ents of a stationary portion ll-of the'variable area nozzle. The movable portion 7 also has a projecting boss 12, which 'contactsfa stop .13 on the guide rods K l K '5' ment, the turbomachine pf Fig d is otherwise the same A V portion 7 is in the fullyiopen posi- 1 tio'nf relative' to the stationary portionilL whereby the tsr eay sl; el men o 11101191116 a P e d. from shifting ea 'ofi mesh with. each other; The stop'13 may be adjusted Fey the threaded ends 'of'itheiguide rods 8, which project through the. plenum Sand maybe locked V in position with nuts 14. d e V 7 Rotation of the turbine Wheel 2;"as shown inFig, 1 7 e is initially inducedby admitting fluid, 'under pressure in the plenum 5, to ,pass through the interleaved nozzle 2,980,394 h i a.

' 10 the variable area nozzle 1 7.

ferentially spaced guide rods '18 and is provided with the; extension '19 to guide movement of the nozzles in addition to providing an 'attachmentfor the elements 16. Except for the;temperature responsive control arrangeas shown in Fig. l.

7 when vlanjncreas in "fluid temperature occurs in the plenurnias" shewninFig. 4, eachot'the bimetal'elemerits 16 will tend to :contract or shorten, thus closing 2 at an'increased' temperature is thereby reduced correspondinglyjp' obtain a constant turbine power output.

When a decrease of fluid lemperatureoccurs 'in the plenum 5, each of the bimetal elements 16 tends to elements 7 and 11mm between. th blade ofthe whe l 15 straighten out or increase in; overall length, thus causing 2'; The energy brine fluid is thenimparted to rotate the Wheel 2 as the fluid 'expands and passes therethrough,

and is exhausted at an outlet 15. j

:A varia'tionin the temperature vofltlzie fluid as it enters the plenum 5 causes thermal stress in the bimetal ele' mentswhich then exert force on the variable area nozzle element 7 to which theeleinents 6. are attached, When the temperatures of fluid in the plenum 5 decreases, the

efiective-over-all length ofthebimetal elements 6 will increase ;thu's' ,"fo'rci'ng T the variable area nozzle, element 7 "to close relative 'to the' stationarynoz'zle lelement ll. The effective. overall length of the. birnetal elements will increase. with a decrease in temperature due to the increase in the radius of thejfolds of the elements caused by the.

different expansion rates oftheiportions 6a and 6b; In

' efiect the bimetal elements will tend .to straighten out'as' the temperature decreases thus increasing the effective overall length of the elements. Fluidflow through the.

wheel 2 is thereby reduced to correspond to the decreased temperature so as to obtain a constant ,reirigeration out- I put of the turbine. When anincrease in fluid'temperature 5, the efiective overall length of occurs in the plenum the bimeta'l elements 6 will decrease, thus opening the variable area nozzle 7." As the temperature increases the radius] of the folds :in the'himetaleelernent will vdecrease thus shortening theoverall length bfthe jelement;

Flnid flowthrough the wheel-2 is'thereby increased to correspond'to the increase in temperature so as to obtain a constant refrigeration output of the turbine. The temperature responsive means; therefore, proportions the,

flow of fluid through the variable area njozzle according to the thermal energy of the fiuid' at the turbine inlet. 7 Attentioniisdirected to Fig. 4 which illustrates a modification of the temperature variable means shown inFigs; v 1 "and, 2. In this modification the mounting of the bimetal elements is changed so that it closes the variable nozzle as'the temperature increases instead of opening it. as described in Fig. 1' which is particularly'adapted for.

use in a power turbine utilized for constant power'o'utput. A plurality otbimetal elements 16 interconnect a movable portion 17 of a variable area nozzleelement and guide rods 18. Eachbimetal element 16 is or a similar construction to the element 6 in Fig. 1 and is made from laminations of two dilferent metals, each metal having a different coefiicient of expansion; The

element is formed 'in a corrugated configuration from individual sections ofthe two laminated metals so that an outside lamination of each section of each fold consists of the metal having the greater coeficient of ex pansion; and the inside lamination of each section of each fold consists of metal having the lesser-coeflicient of expansion; [The'individual' sections are joined by any desired meanssuch as welding or theliker The elements 16 each have one endattached to an extension 19 of the movable-portion 17 f'the variable area nozzle by means of, rivets 20'or other fastening means. The opposite ends of theielements 16 are welded or-suitably fixedto the g ide rods 18.jThe movableportion fl of the variable area nozzle 15: is supported by a plurality of circum- 2: tololitaiii e eerrstentjtnrbine' ewerout ut.

70 Weclaima. e

l aninlet, .me

the variable area nozzle 17 to open. Fluid flow through theiwheel. 2 at. reduced temperature is; thereby increased correspondingly f'to obtain a pons'tan'tlturbinei'power output. 1

20 'ZFigJ 6illustrates a fuither'modification of' the temturbine exhaust ductflfi'. "jEachlternperature responsiveelement-21: consists of a conventional tlierniostatic or temperature sensitive variable element 22 disposed to actuate 'a' 'pistoi1;-23, sothatfan increased temperature of thejvariable e1emem 22' extends the piston zs and ade- 1 crease in temperature permits thejpiston 23 s be. retracted 3 "by a -spring zsa eenne'eted-to beuem'nk '24; Eachbellcranlr'zd'is pivoted on a pin'z lq supported by ears which project radially from. the turbineexhaust" duet 15.1 The g penna t-24 transmits J the foree 6f the temperature responsive {elements Q21 "to thefaxiallfmovable rods 27. 5 Each piston 23 is attachdto one endof abe'llcrahk 24 by e pin 25;; and the other en'd-o'f each bellcrank is attaehed to' one of the rods 'z'n y-e pin 26; "The axially ".i movable rods '27' 'project into the i plenum ;5 and are threaded and the movable portion 28*of the variable area nozzles. The rods NJ-actuate and guide the movable portionY28 ofthervariable area nozzle and are movable axially r elative: to the turbine wheeih-Q Except for the temperature responsive. control arrangement; the turbomachine of Figs. 6 is otherwisethe same 'aslfig. 1.

When exhaust temperature o fitheturhineishown in Fig.6 is reduced below a predetermined value, thejpistons 230i the temperature responsive elements 21contract and are r t ct yg srr nsfifl this mq as the b he ma ab e "Po t o 28 f t e v i e- .a a

When the; inlet fluid temperature throughlthei tu bomaghine' inc'reases, the temperature responsive elements 21in the turbfne exha st. ou l t 5 w l se a i as d temperature a d expan thus v n th i l ia 14 and axially movable rods ,27 in a direction to close the movable'jpjortion 28 of thefvariable areajnozzleirelative to the stationaryportion thereof. Such restriction ofthe nozzle laieal will Tredu'ce thev flu d jflo'wjthI'DHgh the wheel when are .presentinye se n Ised n cooling jturhines,

the toreg'orn temperature responsive. devices maybe disposedfto movie thel 'variable arear-nozzleetbwi lrda closed position when the turbine inlet t'emperature decreases, in order to maintain theturbine, exhaust .at. a jcon'stant temperature' res whine. nastier. means for controlling flow-in turbomachines; a 'turbinev'ivheel having I ans re; 'ingjavariableareatdevice disposed at said inlet tokcontrol don/through saidturhine, a bi- 1. In a. temperature v metal temperature 'sensingelernentdisposed said inlet Fluid flow througheth e wheel to sense fluid temperature therein, said temperature sensing element being connected to said variable area device to actuate the same, and guideways extending axially relative to said turbine wheel and disposed to support both said variable area device and said bimetal temperature responsive device.

2. A temperature responsive variable area nozzle for turbomachines comprising: a turbine Wheel rotatably mounted in a casing; an inlet and outlet formed in said casing for establishing a fluid flow path through said turbine wheel; a variable area nozzle having interleaved vane elements mounted in said casing adjacent said inlet; one of said vane elements being fixed to said casing and the other of said vane elements being supported for axial movement by guide means secured to said casing; an elongated bimetallic element, said bimetallic element having a corrugated axial cross-section, one end of said himetallic element being fastened to said casing and the other end being fastened to said other vane element whereby expansion and contraction of said bimetallic element will position said other vane element.

3. In a temperature responsive variable means for controlling the flow of fluid in turbomachines: a casing having fluid inlet and outlet passages; a turbine wheel rotatably mounted in said casing in the flow between said inlet and outlet passages, the turbine wheel and the inlet and outlet passages forming a flow path for the fluid; a variable area device disposed in said flow path adjacent the periphery of the turbine wheel, said variable area device having interleaved elements movable substantially axially relative to the axis of said turbine wheel to control flow therethrough; an expansion element disposed entirely within said inlet passage and arranged to sense the temperature of the fluid in said inlet passage and to change in overall length in response to changes in the temperature of the fluid therein; means for connecting a portion of said expansion element to said variable area device in a manner to directly impart movement of said expansion element to said axially movable interleaved elements; and guide means in said inlet passage mounted axially relative to said turbine wheel and disposed to support said movable interleaved elements.

4. In a temperature responsive variable means for controlling the flow of fluid in turbomachines: a casing having fluid inlet and outlet passages; a turbine wheel rotatably mounted in said casing in the flow between said inlet and outlet passages, the turbine wheel and the inlet and outlet passages forming a flow path for the fluid; a variable area device disposed in said flow path adjacent the periphery of the turbine wheel, said variable area device having interleaved elements movable substantially axially relative to the axis of said turbine wheel to control flow therethrough; an expansion element disposed entirely within said inlet passage and arranged to sense the temperature of the fluid in said inlet passage and to change in overall length in response to changes in the temperature of the fluid therein; means for connecting a portion of said expansion element to said variable area device in a manner to directly impart movement of said expansion element to said axially movable interleaved elements; and means in said inlet passage forming guide- Ways mounted axially relative to said turbine Wheel and disposed to support both said movable interleaved elements and said expansion element.

References Cited in the file of this patent UNITED STATES PATENTS Buchi Nov. 25, 1958 

